Definition of "vaccinia"

On the other hand, Professor Heim inquired minutely into all the circumstances of the case, and says he is convinced of the variolation of the cow, and of the transmission from her of a disease similar to vaccinia.

1842 May 17, Robert Ceely, “Identity of Small-Pox and Cow-Pock”, in Provincial Medical Journal‎

Since then, a handful of vaccinia cases have been reported to the Centers for Disease Control and Prevention, including one, described in the May 4 Morbidity and Mortality Weekly Report, of vulvar infection in an Alaskan woman whose sex partner was a serviceman.

2007 May 18, John Schwartz, “Soldier’s Smallpox Inoculation Sickens Son”, in New York Times‎